Heterogeneity of Urban Air Pollutants in Ecological Function Zones and Adjacent Zones:a Case Study of the Three Provinces in Northeast China
Assessing the spatial and temporal heterogeneity of air quality in national key ecological functional zones and adjacent zones is of significance for differential air pollution prevention and control.The study is based on AQI and concentra-tion data of six air pollutants(PM2.5,PM10,SO2,NO2,CO,O3)in 13 ecological functional zone cities and 23 adjacent non ecological functional zone cities in Northeast China from 2015 to 2019.Spatial autocorrelation and random forest models are used to analyze the spatiotemporal differences and driving factors of air pollutants.The results show that from the perspective of time scale,compared with 2015,in 2019,except that O3 fluctuated and increased in five years and the average annual con-centration was relatively high,the concentration of other pollutants showed a downward trend,and the air quality of ecological function areas was better than that of non-ecological function areas.The decrease of SO2 concentration(50%)is greater than that of NO2 and CO(20%),and PM25 is greater than PMi0.The highest values of PM25,PM10,NO2,SO2 and CO seasonal varia-tion characteristics appear in winter,and the highest values of O3 are distributed in summer.Monthly average concentration changes in O3 showed a single peak,the highest value in April-July;the monthly average concentration of other pollutants showed a U distribution,with the highest value in November-March(the following year).The cold spots of annual concentra-tion of each pollutant are mainly concentrated in the forest ecological function area of Greater and Lesser Khingan Mountains and the wetland ecological function area of Sanjiang Plain,and the hot spots are mainly concentrated in the non-ecological function area(south area).The distribution pattern of seasonal concentration cold and hot spots is similar to the annual average distribution.Among the natural meteorological factors,the annual average temperature had the greatest impact on AQI and four pollutants except CO and NO2,and the annual average wind speed and vegetation index had a greater impact on SO2.In the socio-economic factors,industrial structure,electricity consumption,traffic factors are the dominant factors affecting the concentration of urban air pollutants.
air pollutantsspatial and temporal distributioninfluencing factorsecological function areanortheast area